Control system for cyclically operated stitching machines having a dual presser foot

ABSTRACT

A control system for cyclically operated stitching machines having a dual presser foot wherein the functions of presser foot manipulation and machine starting are brought about by movement of a single operator control.

United States Patent Tice [54] CONTROL SYSTEM FOR CYCLICALLY OPERATED STITCHING MACHINES HAVING A DUAL PRESSER FOOT [72] Inventor: Richard F. Tice, 4022 Doris Circle, Knoxville, Tenn. 37918 [22] Filed: Nov. 6, 1970 [21] Appl. No.: 87,405

Related US. Application Data [63] Continuation-impart of Ser. No. 739,254, June 24,

1968, Pat. No. 3,565,024,

[52] 11.8. C1.. ...l12/67, 112/219 B, 112/239 [51] Int. Cl ..D05b 3/12, DOSb 69/08 [58] FieldoiSearch ..112/67,87,219B,2l9A,219R,

[ 51 May 9, 1972 [56] References Cited UNITED STATES PATENTS 2,540,987 2/1951 McCann. ....1 12/239 X Myska ..l12/67 Wokeck ..112/67 Primary E.\'aminerl-1, Hampton Hunter Attorney-Anderson, Luedeka, Fitch, Even & Tabin [5 7] ABSTRACT A control system for cyclically operated stitching machines having a dual presser foot wherein the functions of presser foot manipulation and machine starting are brought about by movement of a single operator controL 8 Claims, 9 Drawing Figures ,16 PRESSURIZED FLUID PATENTEDMM 9:972

sum 1 OF 3 Ii h [mi I \10 42 ,16 PRESSURIZED FLU l D 52) INVENTOR.

Rich ard E. Tice BY W, Z MAM 9 x61;

ATTORNEYS PATENTEDHAY '9 I972 3,661 102 SHEET 2 [1F 3 PRESSURIZED 39 FLUID 69 INVENTOR. Richard E. Tice PRESSURIZED F LUI D W flM/ZM, M4 0 ATTORNEYS PATENTEDMAY 9 I972 SHEH 3 OF 3 PRESSURIZED FLUID PRESSURIZED FLUID INVENTOR.

Richa rd E. Tice BY QM flm, fi 6a +72 ATTORNEYS CONTROL SYSTEM FOR CYCLICALLY OPERATED STITCHING MACHINES HAVING A DUAL PRESSER FOOT This application is a continuation-in-part of my copending application Ser. No. 739,254, filed June 24, 1968 entitled Control System for Cyclically-Operated StitchingMachines, now U.S. Pat. No., 3,565,024, dated Feb. 23, 1971.

This invention relates to control systems for cyclically operated stitching machines.

cyclically-operated stitching machines include those stitching machines which, when activated, sew a predetermined number of stitches and then automatically deactivate themselves Control systems for cyclically-operated stitching machines of the type wherein the stitching machine includes a single presser foot for holding the workpiece in position for stitching operations, are known in the art. Such control systems are exemplified by the devices disclosed in U.S. Pat. Nos. 3,245,369, issued Apr. 12, 1966 to G. Myska and 3,298,341, issued Jan. 17, 1967 to G. Bonis. A further control system for single presser foot type stitching machines is disclosed and claimed in my copending application referred to above. However, insofar as I am aware, there are no control systems existing in the prior art whereby stitching machines having a dual presser foot may be controlled through the means of a single control element, such as a single foot pedal.

It is therefore an object of this invention to provide a control system for a cyclically-operated dual presser foot type stitching machine employing a single control element. It is also an object to provide a control system of the stated class wherein the movements of the dual presser foot are controllably effected and are coordinated with the start and stop of the machine. It is a further object to provide a control system for the dual presser foot class of stitching machines whereby positive control over the movements of the dual presser foot, including the ability to raise or lower the second or upper foot element at the will of the operator while maintaining the lower presser foot element in contact with the workpiece and including start of the machine, are accomplished through a single foot pedal operated by the operator. It is also an object to provide a control system of the stated class wherein the control system need not be disconnected from the foot pedal when tilting the machine for maintenance or repair.

Other objects and advantages of the present invention will be recognized from the following description and the accompanying drawings in which:

FIG. 1 is a representation of a dual presser foot type stitching machine having the control system disclosed herein incorporated therewith and showing various features of the invention;

FIG. 2 is a representation of a fluid flow control unit employed in the present invention;

FIG. 3 is a fragmentary view taken along the line3-3 of FIG. 2;

FIGS. 4, 6 and 8 are representations of the control system disclosed herein and illustrating the relationship of various control system components and various components of the stitching machine during three phases of control; and

FIGS. 5, 7 and 9 are fragmentary views taken along the lines 5, 7-7, and 9-9 of FIGS. 4, 6 and 8 respectively.

Insofar as is known, all dual presser foot type machines include two foot elements 9, 14 (see FIG. 1), the first and lower one 9 of which contacts and holds a primary workpiece such as a garment and the second and upper one 14 of which contacts and holds a secondary workpiece such as a label or the like. These machines also include means for spring biasing the two foot elements of the dual presser foot toward their respective work-engaging positions. Each of the first and second foot elements 9, 14 (FIG. 1) of the dual presser foot of this class of stitching machines usually is cantilevered in position to be raised or lowered to and from respective working positions. Each of the foot elements is disposed on means such as a presser foot shaft 12 which is biased toward a work-engaging position by a s ring 24. This shaft 12 is raised against the spring force by means such as a pivoted lever 6.

The first foot element 9 frequently includes a vertical leg 65 slidably fitted within a bore 1 l in the presser foot shaft 12 and supporting the foot element 9 in its cantilevered position over a garment. A spring 13 disposed within the bore 11 provides a downward biasing force against the foot element 9. Upon lowering of the presser foot shaft 12, the cantilevered foot element 9 contacts the garment disposed between the foot and the base and continued downward movement of the shaft 12 causes the vertical leg 65 of the first foot element 9 to retract within the bore 11 against the downward biasing force of the spring 13. By virtue of this or a similar mounting of the first foot element 9 with respect to shaft 12, the shaft may move a selected distance either up or down without moving the first foot element from its workpiece engaging position.

After this first foot element 9 is lowered into position to hold the garment securely, downward movement of the shaft 12 is halted and a label or the like is positioned by the operator on top of the garment (usually within a frame provided on the lowered foot 9) and underneath the cantilevered second foot element 14. Thereupon, further downward movement of the presser foot shaft 12 urges the second foot element into contact with the label to hold it for the duration of a stitching operation designed to attach the label to the garment. Upon completion of the stitching operation, the machine automatically enters the stop mode.

The action of the dual presser foot is preferably sequential; that is, there is a first downward movement of the presser foot by a limited amount whereby the first foot element 9 securely engages the garment interposed between the foot 9 and the base 10. This first movement is followed by a second movement wherein, after the label has been placed in position, the second foot element 14 is lowered into contact with the label to secure it in position for stitching.

Heretofore, the dual presser foot was moved to its raised position by means of a foot pedal connected to the lever 6 by a chain or cable leading from the lever through the platform supporting the machine to the foot pedal disposed on the floor. To lower the dual presser foot, the foot pedal was partially released thereby permitting downward movement of the dual presser foot to where its first foot element contacted the garment. The operator then had to hold the pedal at this position until a label had been placed in position. Thereupon, the foot pedal was released fully to permit the second foot element to engage the label. A second foot pedal similarly connected to a start mechanism on the machine was used to commence a stitching cycle. These prior art foot pedals functioned independently of each other and consequently through operator error in depressing the pedals out of proper sequence, the machine frequently was started prematurely with resultant damage to either the garment of the machine and economic loss.

When tilting these prior art machines with respect to their supporting platform to expose their underside for maintenance or repair, it was necessary to disconnect the foot pedals prior to tilting and to reconnect them when the machine was returned to its upright position. Substantial economic loss was incurred as a consequency of the time and expense involved in making and breaking these connections.

Stated generally, the present invention comprises a control system for a cyclically-operated stitching machine of the type having a dual presser foot, exemplified by the well-known label stitching machine. The control system disclosed herein includes a single operator control mechanically connected to a fluid flow control unit comprising a source of pressurized fluid, first fluid means joining the source of pressurized fluid through a first piston-cylinder unit to the dual presser foot of the machine and operative to raise the foot elements of the presser foot out of their respective work-engaging positions, second fluid means connecting the source through a second piston-cylinder unit to the start mechanism of the stitching machine, and third fluid means connecting the source to a third piston-cylinder unit operative to selectively limit the movement of the dual presser foot. The operator control of the disclosed system includes means disposed adjacent each of the fluid means for selectively effecting fluid flow within each of the fluid means. Interlock means interposed between the source of pressurized fluid and the first and third fluid means is provided to isolate the first and third fluid means from the source of pressurized fluid at all times when the machine is cycling.

A control system is accordance with the present invention is depicted diagrammatically in FIG. 1 as mounted on a label stitching machine 5. This machine is representative of the dual presser foot type stitching machines and it will be recognized that the invention is not restricted to label stitching machines. Rather, the control system disclosed herein is suitable for other cyclically operated stitching machines having a dual presser foot. Being cyclically operated, once the machine is started in motion, it completes a stitching cycle and automatically returns to the stop mode. For purposes of the present discussion, however, the description will be limited to the stitching of a label onto a garment.

With reference to the system depicted in FIG. 1, a first normally closed valve 17 interposed between a source of pressurized fluid l6 and a first piston-cylinder unit 18 connects this first piston-cylinder unit to the source of pressurized fluid, that is, air. The pressurized air is admitted to the cylinder so that its presence causes the piston to move within the cylinder to a position where the piston rod 19 is in a fully extended position. The piston rod 19 of the piston-cylinder unit 18 is connected by means of a pivoted yoke 20 to one end 21 of a lever 6 pivoted to the machine as at 7 and whose opposite end 22 engages a lug 23 on the presser foot shaft 12 so that downward movement of the end 21 of the lever 6 (as viewed in FIG. 1) will result in upward movement of the opposite end 22 of the lever and thereby urge the presser foot shaft 12 upward against the action of a spring 24. Accordingly, when pressurized air is admitted to the cylinder of piston-cylinder unit 18 as noted above, the presser foot shaft 12 is held in its fully raised position and both foot elements 9, 14 are raised to permit the operator to position a garment between the presser foot and a base 10.

After a garment has been placed beneath the presser foot in the depicted system, lowering of the presser foot is accomplished by releasing the air pressure within the cylinder element of piston-cylinder unit 18 to release the lever 6 and permit downward movement of the presser foot. Such release of the pressure within the piston-cylinder unit 18 is effected by selectively closing valve 17 as will be further described hereinafter. Desirably, the presser foot shaft 12 stops its downward movement at the point where the foot element 9 has contacted the garment and prior to lowering of the second foot element 14 into its working position. Accordingly, in the present control system the pivotal motion of lever 6 is halted at the point where the first foot element 9 reaches its position of engagement with the garment. Such restriction of the pivotal movement of the lever 6 is accomplished in accordance with the depicted system, by maintaining pressurized air within the piston-cylinder unit 25, hence maintaining rod 26 of the piston element of the piston-cylinder unit in its extended position so that upon the upward movement of end 21 of the lever 6, the upper edge 28 of the lever contacts the end 27 of the extended rod 26 thereby precluding further upward movement of the lever while piston-cylinder unit 25 is pressurized. Pressurization of piston-cylinder unit 25 is controlled by valve means 37 as will also be further described. Upon placing a label in position for attachment to the garment, depressurization of the piston-cylinder unit 25 releases the piston element of the piston-cylinder unit and permits retraction of its rod 26 thereby freeing lever 6 and permitting the presser foot shaft 12 to move downward under the force of the spring 24 to cause the second foot element 14 to contact and secure the label in position for stitching.

Startup of the machine for cycling through its stitching cycle is accomplished in the illustrated embodiment of FIG. 1, by means of a second piston-cylinder unit 29 having its rod element pivotally joined by a yoke 31 to a pivoted arm 32 whose end 34 is further pivoted to a first clutch element 35 disposed adjacent a second clutch element 36. Pressurization of piston-cylinder unit 29 is controlled by valve means 30. Upon such pressurization of the piston-cylinder unit 29, the rod 30 thereof moves to its extended position thereby pivoting arm 32 to move the first clutch element 35 into engagement with the second clutch element 36 and start the machine cycle. The piston-cylinder unit 29 may be secured to the machine housing as by a bracket 66. The pivoted arm 32 and clutch elements usually are preexisting parts of the stitching machine.

Referring particularly to FIG. 2, selective pressurization of the first, second and third piston-cylinder units 18, 29 and 25, respectively, preferably is effected by means of a fluid flow control unit indicated generally by the numeral 15 including a single lever 38 disposed in juxtaposition to first, second and third valves and movable with respect to the valves by means of an operator control such as a single foot pedal 39 connected to the lever 38 by a chain means 40. The lever 38 is pivoted as by bolt means 41 to a support plate 42 secured to a table 71 or other supporting surface upon which the stitching machine rests. The limits of travel of lever 38 are established by lugs 43, 44 secured in support plate 42. ln the illustrated fluid control unit, the lever 38 is biased by means of spring 45 to a first stop position against lug 44 but is movable from this position to a second stop position against lug 43 by depression of the foot pedal 39 by an operator. Through depression of the foot pedal 39, an operator can move the lever 38 to any desired position intermediate of the two stop positions.

Preferably, each of the valves employed in the disclosed control system is of the normally closed type, that is, the spindle of each valve is biased in its extended position thereby closing the valve against fluid flow therethrough. Moreover, each of the valves has means associated therewith for exhausting pressure downstream of the valve when the valve is in the closed position. In the valves depicted in the Figures, this exhaust means comprises an opening 51 provided in each valve spindle and leading from the interior of the valve to ambient atmosphere.

When the lever 38 is in its stop position against lug 44, the lever contacts the spindle 46 of the normally closed first valve 17 whose inlet 47 is teed into a line 50 leading from the source of pressurized fluid 16, through a valve means 67, to the first valve 17. The outlet 49 of first valve 17 is connected to line 48 which is in turn connected to the first piston-cylinder unit 18.

The spatial relationship between the valve 17 and lever 38 when it is in its stop position against lug 44 is chosen such that the spindle 46 of the valve 17 is maintained in its nonextended position, thereby maintaining valve 17 open for the flow of fluid therethrough at all times when lever 38 is in its stop position against lug 44. Since lever 38 is only against lug 44 when the foot pedal 39 is in the raised position, and because the lever 38 is biased against stop 44, valve 17 will remain open for the flow of fluid therethrough at all times when the foot pedal 39 is released by the operator. As noted above, the open or closed status of the valve 17 determines the activation or deactivation of piston-cylinder unit 18, subject however to the functioning of an interlock valve 67 as will appear hereinafter.

A second normally closed valve 30 is disposed on the opposite side of lever 38 from valve 17. The spindle 52 of this second valve, when in its extended position, is disposed adjacent, but not in contact with, lever 38. The inlet 53 to valve 30 is connected to the pressurized fluid source and the outlet 54 of the valve 30 is connected to a line 55 which leads to the second piston-cylinder unit 29. From viewing FIG. 2, it will be seen that when the foot pedal 39 is fully depressed by an operator, the lever 38 will be moved downwardly against the force of spring 45 into contact with the extended spindle 52 of the second valve 30 thereby opening the valve to permit the flow of pressurized fluid therethrough and to the pistoncylinder unit 29. Activation of piston-cylinder unit 29 starts the machine stitching cycle.

A third normally-closed valve 37 is mounted by a bracket means 56 to the support plate 42. The position of this third valve 37 with respect to lever 38 is chosen such that the spindle 57 of the valve is disposed perpendicularly to lever 38 as depicted in FIG. 3. This spatial relationship also provides for depression of the spindle when it is contacted by the lever 38. In the preferred embodiment, this spindle 57 is provided with a rounded terminus so that as arm 38 is pivoted into contact with the spindle, a wedging force is developed which causes the spindle to retract and open valve 37. Notable, and for purposes which will appear more fully hereinafter, when the spindle 57 is in contact with the lever 38 and held fully retracted, the lever 38 remains in sliding engagement with the spindle and can move a substantial distance without changing the position of the spindle, hence the open or closed status of the valve 37. Specifically, the width of the lever 38 is chosen to be sufficiently wide that it can be moved through several degrees of arc from the position of the lever where it causes full retraction of the spindle 57 and the position of the lever where it disengages the spindle 57 to permit movement of the spindle 57 to its extended position. By this design, the valve 37 may be maintained open by the lever 38 while the lever is moved a distance sufficient to move the lever out of contact with spindle 46 of valve 17 and close valve 17. In order to obtain this simultaneous control over the two valves 17, 37 with the single lever 38 it is preferred to locate the valve 37 a greater radial distance from the pivotal mounting 41 of the lever 38 than the valve 17.

The inlet 58 of the valve 37 is connected to the line 50 leading from the source of pressurized fluid, through valve 67, to valve 37. The outlet 59 of the valve 37 is connected to a line 60 which joins the valve 37 to the third piston-cylinder unit 25 whose function is to controllably limit the downward movement of the presser foot as noted hereinbefore.

Interlock means in the form of a normally-closed valve 67 is interposed in line 50 between the source of pressurized fluid 16 and valves 17 and 37. The spindle 68 of the valve 67 preferably is disposed adjacent the end 34 of the pivoted arm 32 which moves the clutch elements into and out of engagement and is held retracted (opening valve 67) when the machine is stopped and the clutch elements are disengaged to pivot arm 32 against the spindle. Thus, valve 67 is held open and air flows from the source 16 to valve 17 and 37 only when the machine is not operating thereby insuring that pistoncylinder unit 18 cannot be pressurized to raise the presser foot rematurely of the completion of the machine stitching machine. In addition, the isolation of the first and third valves 17 and 37 from the source of pressurized fluid while the machine is cycling permits the return of the lever 38 to its stop position against the lug 44 after the machine is started thereby permitting the operator to release the foot pedal at any time after the cycle commences. The operator is thus relieved of any concern regarding holding the pedal down for the duration of the machine cycle or concern for inadvertent depression of the pedal and accompanying malfunctioning of the machine. In this way, the operator is free to concentrate on other functions and as a result the efficiency of the operator is increased.

Operation of the control system disclosed herein is depicted schematically in FIGS. 4 through 6. Three stages of control are shown. In the first stage (FIG. 4), the machine is depicted in the stop mode. In this stage, the clutch elements 35, 36 are disengaged and arm 32 is pivoted against the spindle 68 of the valve 67 to open the valve 67 thereby admitting pressurized air into line 50 as far as the valves 17 and 37. Also in this control stage, the foot pedal 39 is in its released position (up position due to bias force of a spring 69) and lever 38 is biased against lug 44 thereby simultaneously opening valves 17 and 37 to admit pressurized air to piston-cylinder units 18 and 25, respectively. The pressurized fluid in piston-cylinder unit l8 causes the rod element 19 thereof to extend, forcing end 21 of lever 6 downward and holding the presser foot shaft 12 upward against the biasing force of spring 24. Also in this control phase, the lever 38 is moved away from the spindle 52 of the valve means 30 thereby permitting the spindle thereof to extend and close valve 30 and block the flow of pressurized air therethrough. The extended valve spindle permits exhausting of the pressure downstream of the valve 30 through opening 51 in the spindle, thereby releasing the pressure from pistoncylinder unit 29.

The position of lever 38 with respect to the spindle 57 of the valve 37 during this first stage of control is depicted in the fragmentary view of FIG. 5. In this first stage, the lever 38 is in contact with the spindle 57 and the valve 37 is held open thereby admitting pressurized air to piston-cylinder unit 25 and maintaining rod 26 extended to halt subsequent upward movement of end 21 of the lever 6. The distance between the end 27 on extended rod 26 and the upper edge 28 of the end 21 of the lever 6 is selected so that as the pressure foot shaft 12 is lowered, movement of the lever.6, hence downward movement of the shaft 12, will be halted by the lever 6 contacting the extended rod 26. This contact occurs, by design, when the shaft 12 has moved downwardly sufficiently for the first foot element 9 to engage the garment. This position of the foot element and the relative positions of the lever 6 and rod 26 are shown in FIG. 6.

This latter Figure depicts a second stage of control. After an operator has positioned a garment between the foot element 9 and the base 10, downward movement of the presser foot shaft 12 is commenced by the operator depressing the foot pedal 39 through about half of its range of movement. This movement of the pedal moves the lever 38 away from the spindle 46 of the valve 17, thereby closing the valve to block the flow of pressurized air therethrough and exhaust the pressure downstream to piston-cylinder unit 18. Upon release of such pressure, the piston element of the piston-cylinder unit 18 becomes free and the force of spring 24 commences the pivotal movement of shaft 12 downward to move the foot elements 9, 12 toward their work-engaging positions.

This initial depression of the foot pedal and movement of the lever 38 does not change the open state of the valve 37 (see FIG. 7), thus the rod 26 of the piston-cylinder unit 25 remains extended to halt the downward movement of the presser foot shaft as described above.

With the garment thus secured, the operator may next place a label or other item in position on the secured garment and depress the foot pedal a further distance to move lever 38 out of contact with spindle 57 of the valve 37 as depicted in FIG. 9. This movement of the lever 38 permits the spindle 57 to extend and close the valve 37, thereby blocking the flow of pressurized air therethrough. Simultaneously, the pressure downstream to piston-cylinder unit 25 is exhausted. With this pressure relieved, the piston element of piston-cylinder unit 25 and its rod 26 are freed and shaft 12, being no longer restrained, moves to its fully down position, causing the second foot element 14 to secure the label for stitching. As the second foot element 14 is lowered, the leg 65 of the first foot element 9 enters the opening 11 in the shaft 12 against the force of the spring 13 thereby accommodating the relative movement between the two foot elements 9, 14.

Since the lever 38 is so positioned relative to the spindle S7 of the valve 37 that the lever may be moved a distance sufficient to open or close the valve 17 without closing valve 37, the operator may at will raise or lower the presser foot shaft 12 by an amount sufficient to move the first foot element 9 between its working and non-working positions. This allows the operator to raise the first foot element and reposition a garment disposed thereunder in the event the garment is improperly positioned in the first instance. By reason of the present control system, it is possible with only a single foot pedal to stop the sequence of operator activities and back up to correct an error without loss due to a damaged garment or wasteful use of time. In addition by widening lever 38 or by securing a' slide plate thereto, the distance which the lever needs to be moved between the point where the valve 17 is closed and the valve 37 is closed may be readily adjusted over a considerable range. Trainee operators may thus be provided with machines which provide considerable leeway in the positioning of the foot pedal or the delay time between the sequential closing of the valves 17 and 37 (the delay time between securing the garment and securing the label) may be shortened to increase the productivity of experienced operators.

With reference to FIG. 8, by depressing the foot pedal 39 still further, the operator may move the lever 38 into contact with spindle 52 of the valve 30, thereby opening this valve to admit pressurized air to piston-cylinder unit 29 and extend rod 30 thereof, rotating arm 32 to cause engagement of clutch elements 35, 36 and starting of the stitching cycle. As the arm 32 moves away from the spindle 68, the spindle protracts and closes valve 67, shutting off the flow of pressurized air to the valves 17 and 37. At this point, the operator may release the foot pedal and permit the lever 38 to move under the influence of spring 45 to its stop position against lug 44 in position for commencement of a subsequent cycle. Notably, this return of the lever to its stop position against lug 44 produces no immediate change in the status of piston-cylinder units 18 and 25 so long as the machine is operating and valve 67 is closed. When the machine stops and valve 67 is again opened, piston-cylinder units 18 and 25 are actuated as the machine stops, thereby raising the presser foot shaft 12 fully to free the garment with its attached label. The control system thus is positioned for commencement of a subsequent cycle, the lever 38 already being in position as noted above.

Control systems in accordance with the present disclosure have been installed on existing dual presser foot stitching machines and tested by operators having experience with the prior art control systems. In all instances, the operators quickly adapted to the new control system and indicated a preference for the present control system. With the present control system the operators were consistently able to increase their productivity. Instances of damage to the garment or machine as a consequence of the machine functioning out of sequence have not been noted.

The usual stitching machine is mounted on a supporting surface such as a table 42 but tiltable with respect thereto, as by hinge means 70, to expose the underside of the machine for repair or maintenance purposes. In the present control system, each of the piston-cylinder units is mounted in a position located on the upper side of the supporting surface as distinguished from mounting the unit below the supporting surface. Further, the lines leading to the piston-cylinder units are preferably flexible. By this positioning of the piston-cylinder units the control system introduces no restriction or limitation upon tilting of the machine; but rather the several components of the disclosed control system are disposed on or about the machine so as to permit ready tilting of the machine without disconnecting or otherwise having to remove or relocate one or more of the system components. This latter capability is contrary to the prior art double foot pedal type controls and affords a savings over the prior art in connection with machine repair and maintenance.

The number of components in the illustrated control system is minimal for performing the desired functions and the system is of uncomplicated structure thereby making it inexpensive to manufacture. The components are readily mountable on existing machines with little or no alteration of the machine, making it expedient to convert from the prior art control systems to the more desirable system disclosed herein.

While a preferred embodiment has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims. For example, in the depicted embodiment, the position of the piston-cylinder units with respect to the lever 6 may be changed to positions to the right of the pivotal mounting 7 of the lever. In such an alternative arrangement, the piston-cylinder units would be of the type such that upon their being pressurized, they would exert a pulling force upon the lever 6 to raise the presser foot shaft 12. Other positions of the piston-cylinder units, such as below the lever 6 rather than above it, will be apparent in view of the present disclosure. It will also be apparent to employ means other than a lever to ef fect raising of the presser foot shaft.

What is claimed is:

1. In a platform mounted cyclically operated stitching machine of the class having a dual presser foot including first and second foot elements movable between respective workengaging and nonwork-engaging positions, said foot elements being resiliently biased toward their respective work-engaging positions, a cycle actuator, means reciprocatable in response to start and stop motion of said machine, and means to permit tilting of said machine with respect to said platform to expose the underside of said machine, an improved control system comprising first, second and third piston-cylinder units, each of said piston-cylinder units including a piston rod element which is movable in response to the admission of pressurized fluid into the cylinder portion of such pistoncylinder unit, said piston rod of said first piston-cylinder unit being connected to said dual presser foot and operative to move said first and second foot elements of said dual presser foot to their respective nonwork-engaging positions upon the admission of pressurized fluid to the cylinder portion thereof, said piston-rod of said second piston-cylinder unit being connected to said cycle actuator for commencing a stitching cycle of said machine upon the admission of pressurized fluid to the cylinder portion thereof, said piston rod of said third pistoncylinder unit being disposed in a position to releasably hold said dual presser foot in a position wherein said first foot element of said dual presser foot is in its work-engaging position and said second foot element of said dual presser foot is out of work-engaging position, upon the admission of pressurized fluid to the cylinder portion thereof,

a source of pressurized fluid,

conduit means connecting said piston-cylinder units to said source of pressurized fluid, at least a portion of said conduits being flexible to permit tilting of said machine with respect to its platform mount, first, second and third control valve means interposed in said conduit means between said source of pressurized fluid and said piston-cylinder units, the open or closed status of each of said control valve means controlling the flow of pressurized fluid to said piston-cylinder units,

operator control means including a valve actuator disposed adjacent said first, second and third control valve means whereby movement of said valve actuator sequentially changes the open or closed status of said first, second and third control valve means and in like sequence causes the pressurization within each cylinder portion of each of said piston-cylinder units to change so that sequentially the first foot element of said dual presser foot moves to its work-engaging position, said second foot element of said dual presser foot moves to its work-engaging position and the stitching cycle of said machine commences, and upon the completion of said stitching cycle said machine stops and said first and second foot elements of said dual presser foot move to their respective nonwork-engaging positions, and

interlock valve means interposed in said conduit means between said source of pressurized fluid and said first and third control valve means, said interlock valve means being disposed adjacent said means reciprocatable in response to start and stop motion of said machine whereby reciprocation of said means functions to close said interlock valve means when said machine is cycling and to open said interlock valve means when said machine is in the stop mode, to isolate said source of pressurized fluid from said first and third piston-cylinder units when said machine is cycling.

2. The invention of claim 1 wherein each of said first, second and third piston-cylinder units are disposed on or above the upper surface of said platform and at least that portion of said conduit means which connects said first, second and third piston-cylinder units to their respective control valve means is flexible thereby permitting said machine to be tilted with respect to its platform without disconnecting any part of said control system.

3. The invention of claim 1 wherein said piston-cylinder units are of the single-acting class and said control valve means are of the normally-closed class.

4. The invention of claim 3 wherein said valve actuator is movable between first, second and third positions and operative to maintain said first and third valves open while in its first position, to maintain said third valve open when in its second position, and to maintain said second valve open when in its third position.

5. The invention of claim 4 wherein said third valve includes a reciprocatably mounted spindle therein which functions to open said third valve when said spindle is depressed, and said valve actuator comprises an elongated rigid member pivoted at one of its ends and having its other end free to move in an arcuate path in response to movement of said operator control means, said member having a flat side portion slidably receiving said spindle of said third valve whereby said third valve is maintained open when said member contacts and depresses said spindle.

6. The invention of claim 5 wherein said flat side portion is dimensionally sufficient to permit said valve actuator to move out of contact with said first valve. while still maintaining sliding contact with said spindle of said third valve means thereby being movable to close said first valve without closing said third valve.

7. The invention of claim 6 wherein the axis of reciprocation of said spindle of said third valve means is disposed substantially perpendicularly to said flat side portion of said elongated member and said spindle is provided with a rounded head for facilitating the engagement of said member with said spindle as said member is pivoted.

8 In a cyclically-controlled stitching machine of the class having a dual presser foot including first and second elements movable between respective work-engaging and nonwork-engaging positions, said foot elements being resiliently biased toward their respective work-engaging positions, a cycle actuator, and a machine member movably responsive to startstop motion of said machine, an improved control system comprising a first piston-cylinder unit connected to said dual presser foot for effecting the raising of the foot elements of said dual presser foot away from their respective work-engaging positions,

a second piston-cylinder unit connected to the cycle actuator of said machine for commencing the stitching cycle of said machine,

a third piston-cylinder unit disposed adjacent said dual presser foot and releasably halting the lowering of said dual presser foot at a point where said first foot element has reached its work-engaging position but said second foot element is out of its work-engaging position,

a source of pressurized fluid, means connecting said pistoncylinder units to said source of pressurized fluid, said means including a plurality of control valve means whose respective open or closed status controls the flow of pressurized fluid from said source to said piston-cylinder units,

operator control means including a single valve actuator disposed adjacent said control valve means whereby movement of said valve actuator sequentially changes the open or closed status of said control valve means and in like sequency effects the lowering of said first foot element to its work-engaging position, the lowering of said second foot element to its work-engaging position, c0mmencement of the stitching cycle of said machine, and return of said first and second foot elements to their respective nonwork-engaging positions when said machine next enters the stop mode, and,

interlock valve means included in said means connecting said source of pressurized fluid to said piston-cylinder units and operative in response to start and stop of said stitching machine to isolate said source of pressurized fluid from that part of said means connecting said source to said first and third piston-cylinder units at all times when said machine is stitching.

UNITED STATES PATENT oTTTcE QERTIFICATE OF QUREC'HGN Patent No. a Dated May 9 1972 Inventor(s) Richard E. TiCe It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the title page, Item [72], change the inventor's name from "Richard F. Tice" to Richard E. Tice--.

Column 3, line 10, change "is" (first occurrence) to --in-- Column 10, line 30, change "sequency" to --sequence--.

Signed and sealed this 21st day of November 1972.

(SEAL) Attest:

EDWARD M.FLETCEER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents ORM PO-105OHO-G9) USCOMM-DC 60376-P69 U.$ GOVERNMENT PRINTING OFFICE: 1969 O365334 

1. In a platform mounted cyclically operated stitching machine of the class having a dual presser foot including first and second foot elements movable between respective work-engaging and nonwork-engaging positions, said foot elements being resiliently biased toward their respective work-engaging positions, a cycle actuator, means reciprocatable in response to start and stop motion of said machine, and means to permit tilting of said machine with respect to said platform to expose the underside of said machine, an improved control system comprising first, second And third piston-cylinder units, each of said piston-cylinder units including a piston rod element which is movable in response to the admission of pressurized fluid into the cylinder portion of such piston-cylinder unit, said piston rod of said first piston-cylinder unit being connected to said dual presser foot and operative to move said first and second foot elements of said dual presser foot to their respective nonwork-engaging positions upon the admission of pressurized fluid to the cylinder portion thereof, said piston-rod of said second piston-cylinder unit being connected to said cycle actuator for commencing a stitching cycle of said machine upon the admission of pressurized fluid to the cylinder portion thereof, said piston rod of said third piston-cylinder unit being disposed in a position to releasably hold said dual presser foot in a position wherein said first foot element of said dual presser foot is in its work-engaging position and said second foot element of said dual presser foot is out of work-engaging position, upon the admission of pressurized fluid to the cylinder portion thereof, a source of pressurized fluid, conduit means connecting said piston-cylinder units to said source of pressurized fluid, at least a portion of said conduits being flexible to permit tilting of said machine with respect to its platform mount, first, second and third control valve means interposed in said conduit means between said source of pressurized fluid and said piston-cylinder units, the open or closed status of each of said control valve means controlling the flow of pressurized fluid to said piston-cylinder units, operator control means including a valve actuator disposed adjacent said first, second and third control valve means whereby movement of said valve actuator sequentially changes the open or closed status of said first, second and third control valve means and in like sequence causes the pressurization within each cylinder portion of each of said piston-cylinder units to change so that sequentially the first foot element of said dual presser foot moves to its workengaging position, said second foot element of said dual presser foot moves to its work-engaging position and the stitching cycle of said machine commences, and upon the completion of said stitching cycle said machine stops and said first and second foot elements of said dual presser foot move to their respective nonwork-engaging positions, and interlock valve means interposed in said conduit means between said source of pressurized fluid and said first and third control valve means, said interlock valve means being disposed adjacent said means reciprocatable in response to start and stop motion of said machine whereby reciprocation of said means functions to close said interlock valve means when said machine is cycling and to open said interlock valve means when said machine is in the stop mode, to isolate said source of pressurized fluid from said first and third piston-cylinder units when said machine is cycling.
 2. The invention of claim 1 wherein each of said first, second and third piston-cylinder units are disposed on or above the upper surface of said platform and at least that portion of said conduit means which connects said first, second and third piston-cylinder units to their respective control valve means is flexible thereby permitting said machine to be tilted with respect to its platform without disconnecting any part of said control system.
 3. The invention of claim 1 wherein said piston-cylinder units are of the single-acting class and said control valve means are of the normally-closed class.
 4. The invention of claim 3 wherein said valve actuator is movable between first, second and third positions and operative to maintain said first and third valves open while in its first position, to maintain said third valve open when in its second position, and to maintain said second valve open when in its third position.
 5. The invention of claim 4 wherein said third valve includes a reciprocatably mounted spindle therein which functions to open said third valve when said spindle is depressed, and said valve actuator comprises an elongated rigid member pivoted at one of its ends and having its other end free to move in an arcuate path in response to movement of said operator control means, said member having a flat side portion slidably receiving said spindle of said third valve whereby said third valve is maintained open when said member contacts and depresses said spindle.
 6. The invention of claim 5 wherein said flat side portion is dimensionally sufficient to permit said valve actuator to move out of contact with said first valve while still maintaining sliding contact with said spindle of said third valve means thereby being movable to close said first valve without closing said third valve.
 7. The invention of claim 6 wherein the axis of reciprocation of said spindle of said third valve means is disposed substantially perpendicularly to said flat side portion of said elongated member and said spindle is provided with a rounded head for facilitating the engagement of said member with said spindle as said member is pivoted. 8 In a cyclically-controlled stitching machine of the class having a dual presser foot including first and second elements movable between respective work-engaging and nonwork-engaging positions, said foot elements being resiliently biased toward their respective work-engaging positions, a cycle actuator, and a machine member movably responsive to start-stop motion of said machine, an improved control system comprising a first piston-cylinder unit connected to said dual presser foot for effecting the raising of the foot elements of said dual presser foot away from their respective work-engaging positions, a second piston-cylinder unit connected to the cycle actuator of said machine for commencing the stitching cycle of said machine, a third piston-cylinder unit disposed adjacent said dual presser foot and releasably halting the lowering of said dual presser foot at a point where said first foot element has reached its work-engaging position but said second foot element is out of its work-engaging position, a source of pressurized fluid, means connecting said piston-cylinder units to said source of pressurized fluid, said means including a plurality of control valve means whose respective open or closed status controls the flow of pressurized fluid from said source to said piston-cylinder units, operator control means including a single valve actuator disposed adjacent said control valve means whereby movement of said valve actuator sequentially changes the open or closed status of said control valve means and in like sequency effects the lowering of said first foot element to its work-engaging position, the lowering of said second foot element to its work-engaging position, commencement of the stitching cycle of said machine, and return of said first and second foot elements to their respective nonwork-engaging positions when said machine next enters the stop mode, and, interlock valve means included in said means connecting said source of pressurized fluid to said piston-cylinder units and operative in response to start and stop of said stitching machine to isolate said source of pressurized fluid from that part of said means connecting said source to said first and third piston-cylinder units at all times when said machine is stitching. 